This invention relates to a friction lining warning device for a pin-guided spot-type disc brake in which electrical switches are responsive to movement of a stud which engages the pin.
German patent application No. 29 29 039 discloses a friction lining warning device which is arranged between an end section of a brake carrier and a pin and is connected to the pin. The friction lining warning device has a housing forming a second component which is fastened to an end section of the brake carrier, and a rod-shaped sensor forming a first component fixed to the pin in a friction-type locking fit by means of a lock washer. A stop element is positioned within the housing against which the end of the sensor is abutted in order to limit the motion of the sensor into the housing. When fastening the friction lining warning device in the brake carrier, particularly in the pin, difficulties are encountered, especially when fixing the sensor in the pin. This is because the depth of penetration of the sensor in the pin defines a position of the housing relative to the sensor and the depth of penetration cannot be controlled. The indication of the wear of the lining depends on the relative position between the sensor and the pin. In the event of an incorrect mounting, the device fails to indicate correctly or the friction lining warning device becomes detached from the disc brake.
It is the object of the invention to improve a wear-resistant, reusable friction lining warning device and to improve the indication of the wear of the lining warning device and to improve the indication of the wear of the lining. The fixing is to be safe and reliable. In particular, a plurality of warning points indicating different thicknesses of the friction lining to a driver or to a workshop are to be positioned in the warning device.